Error exporting animation as GLTF file
Here's how I got it to work:

1) Upgrade to the latest Blender 2.8.1

2) Go to export panel:

Export -&gt; glTF -&gt; Presets


3) Set the options:

Transform -&gt; +Y Up
Animations -&gt; Always sample animations


4) Test your exported animation in a viewer:

https://gltf-viewer.donmccurdy.com/